Have you ever wondered which breed of dog barks the most, why black cats are a sign of good luck or which direction dogs wag their tail to show they are happy? Here are 36 fascinating facts from a new book on man's two best friends...

Dogs can smell human fingerprints that are a week old. Their noses are so sensitive that they can even smell electricity. While conducting an experiment, a researcher found that a dog could smell which of two boxes contained an electric current.

He concluded this was because the charge resulted in the release of tiny amounts of ozone that the dog could detect. The source of the dog's exceptional ability to smell is its wet snout.

The moist leathery surface acts like Velcro, catching even the tiniest molecules of smells, then dissolving them so that the dog's internal smell-receptor cells can analyse them properly. To keep its nose wet, a dog must produce a constant supply of mucus through the nasal cavities. Scientists reckon the average dog produces a pint of this mucus every day.

Apparently dogs prefer Bach to BritneyDogs prefer Bach to Britney. A study looked at the way hundreds of distressed rescue dogs reacted to different kinds of music. The sound of human voices and pop music by artists like Britney Spears did nothing to calm the stressed dogs. Heavy metal and grunge music made the dogs even more agitated. When the band Metallica were played, for instance, the dogs started barking loudly.

At the other end of the scale, however, the scientists discovered that dogs relaxed and enjoyed themselves most when they were played classical music. Naturally, they liked the sound of Bach in particular.

Male dogs tend to be left-pawed, while females favour their front right paw. Cats, on the other hand, are generally left-pawed. Studies found that 20 per cent of cats favoured their right paws when carrying out complicated, manipulatory tasks such as toying with objects, while a little over 38 per cent favoured their left. The remaining 42 per cent were ambidextrous.

Many owners think their cat senses their arrival home in the car: The truth is more likely to be that its ultrasonic hearing allows it to recognise the signature high-frequency sound of the owner's car well in advance of its arrival within human earshot.

The ten brightest breeds of dog (ranked according to their ability to understand new commands in fewer than five repetitions and to obey first commands 95 per cent of the time or better) are: 1 Border Collie; 2 Poodle; 3 German Shepherd; 4 Golden Retriever; 5 Doberman Pinscher; 6 Shetland Sheepdog; 7 Labrador Retriever; 8 Papillon; 9 Rottweiler; 10 Australian Cattle Dog.

Cats only have 30 teeth compared to dogs which have 42Dogs have 42 teeth. Cats only have 30. The make-up of their mouths reflects their different dietary habits. At the front of the mouth, both have six incisors and two canines, used primarily for ripping. At the back of the mouth, however, dogs have more molars and premolars. These are used chiefly for crushing plants, roots, vegetables and bone, which cats don't eat.

Happy dogs wag their tails predominantly to the right. A study of how dogs respond to different stimuli was conducted by Italian neuroscientists and vets. Over a month, they watched a group of 30 dogs respond when they were briefly joined in turn by their owner, an unfamiliar human, a cat or an unfamiliar dominant dog, a Belgian Shepherd. The dogs' tails wagged vigorously to the right when they were shown their owners and much less so when they saw the unfamiliar human.

Cats lick themselves to protect against both the cold and excessive heat. In cold weather, licking helps to keep their fur smooth so that it functions as a more efficient layer of insulation. In hot weather, licking compensates for the cat's lack of sweat glands and helps to cool down the fur. Historically, cats have been regarded as valuable weather forecasters.

Hungry cats can meow at the rate of two per minute for more than two hours non-stop and can purr continuously for up to two hours. Adult cats convey different signals with a dozen different sounds. They signal territorial aggression by growling, howling and snarling, and defensiveness by spitting and hissing. The meow, trill and chirrup sounds signal greetings. Cats also gurgle. Scientists think this is a signal of friendship.

Cats and dogs are good for human health. The idea that pets may help prevent illness was raised in the 1980s when Erica Friedmann at the University of Maryland found that recovering heartattack patients tended to live longer if they had cats or dogs.

Female dogs have a lower boredom threshold than males. In a major study in which both sexes were encouraged to look at a selection of different humans, the females got bored more quickly than the males.

A dog's bark lasts on average for 0.2 secondsA dog's barks last, on average, for 0.2 seconds each. A Beagle was once recorded barking 907 times in ten minutes. Some dogs are more likely than others to be guilty of excessive barking. Highest-ranking breeds: Yorkshire Terrier, Cairn Terrier, Miniature Schnauzer, West Highland White Terrier, Fox Terrier, Beagle.

Dogs are born with an equivalent of a thumb on the side of their feet. The extra digit, the dew claw, is a remnant of their evolutionary past that has become obsolete. The dew claw can be a handicap for working dogs in particular, as it can get caught in undergrowth and bushes.

Dogs can tell the time. During his famous experiments, the Russian physiologist Ivan Pavlov trained dogs to expect to receive food every half an hour. But when he changed the rules of the experiment and failed to give them anything, they still started salivating after almost exactly 30 minutes. Consciously or unconsciously, their internal clocks had told them to expect food.

The cat's purr may be a self-healing mechanism. Cats purr at between 25 and 50 hertz, a frequency at which vibrations have been found to have a wide range of medical benefits, from increasing bone density and helping in the healing of fractures, torn tendons and muscles to generally relieving pain.

Cats are highly promiscuous. Male cats aren't fussy about who they mate with.

Cats have more than 20 muscles in their external ears, or pinnae. As a result, they can move each ear independently of the other, using them to identify and amplify sounds quickly. They can also move their bodies in one direction while pointing their ears in another.

When researchers tracked the behaviour of a white tomcat for a year, they found he fathered 63 kittens with a number of different females. That's one every six days or so.

Male cats appear to be possessive and certainly don't like the idea of sharing. Indeed, knowing their partners are being "unfaithful" makes them less fertile. One study of the sexual activity of male cats found some were capable of having sex ten times in an hour.

An average mother cat has between one and eight kittens per litter, though a litter may contain as many as 13 kittens. In one case, a cat was discovered to be carrying 18 foetuses. One cat was recorded as having 420 kittens over a period of 17 years. The oldest known mother was pregnant at the age of 26.

Cats' milk contains eight times more protein and three times as much fat as human milk.

Dogs have more taste-buds than cats. They have around 1,700 - almost four times as many as cats, which have approximately 470. A cat's tastes are moulded when it is a kitten. During weaning its mother gives it a set of food preferences which remains in place for the rest of its life. From then on, a cat is extremely fussy about eating anything that it hasn't tried before. So, despite the fact that raw meat is closer to the diet it would have in the wild, a domesticated cat raised on tinned cat food will shun uncooked cuts of meat that don't look and smell like the processed product.

Cats are hypercarnivores. This means they need a much higher amount of protein in their diet than almost any other mammal. An adult cat needs its diet to contain 12 per cent protein while a kitten needs half as much again, 18 per cent. Dogs are capable of living healthily on much less than this. An adult dog needs a diet of only 4 per cent protein. This is why dogs are much better suited than cats to vegetarian diets.

Cats can fish. To land their catches, they use a cunning "flip" technique. Depending on the size of their prey, they will dip one or two front paws into the water and quickly slide them under the fish's belly. They will then flip the fish out of the water, throwing it behind them, over their heads and on to land, where they will eat it. When kittens throw a ball up into the air as if to catch it, they are not playing. In fact, they are practising the fishing techniques they would use if they were living in the wild.

Chocolate can be poisonous to a dog because it contains high levels of theobromine, which is a cardiac stimulant and diuretic. Cats don't like sweet things, mainly because they can't taste them. By analysing the cat's genetic code, scientists learned that part of the code that normally provides an animal with sweet-taste receptors is missing.

Cats are much less likely to become overweight than dogs. One vet reported that 30 per cent of dogs that came to his clinic were overweight. Only 10 per cent of cats suffered from obesity. Anorexia is more common in cats than dogs, though dogs can suffer from it. In their case, the condition is often associated with anxiety about being separated from their owners.

Contrary to the familiar saying, old dogs can learn new tricks - provided, that is, they are following a healthy lifestyle. A study discovered that when elderly Beagles were fed on a diet of fruit, vegetables and vitamins and exercised regularly, they were able to learn a whole range of new tasks. Scientists think the healthy regime and mental stimulation stave off the onset of Alzheimer's and other brain-related illnesses common in older dogs.

The cat has a symmetrical walk, with its left limbs moving in sequence together, half a stride apart from its right limbs. The giraffe and the camel are thought to be among the few other animals that walk thisway. Cats normally walk at around 0.9 metres a second - that's just over 2mph. Most breeds of domestic cat can run at speeds of up to 30mph. The Egyptian Mau, exceptionally fast, can reach up to 36mph.

Cats instinctively react to cold by baring their teeth and walking around in circles.

All 38 members of the modern cat family are believed to be descended from just eight ancestors: the ocelot, panther, caracal, baycat, Asian leopard, puma, lynx and the domestic cat. The domestic cat evolved from the African wild cat and six species of small cats that thrived around the Mediterranean.

Cats signal friendship by sticking their tails in the air. Scientists think this might be a rare case of a behaviour that has evolved since the domestic cat started living with humans. In the wild, cats raise their tails into an upright position only in order to spray urine. A household cat, however, adopts this position for long periods of time while it conducts friendly rubbing with another cat.

Black cats shouldn't he seen as symbols of bad luck - quite the opposite, in fact. Scientists have discovered that, if anything, black cats have a fortunate genetic make-up. The gene for melanism, which makes their fur black, may also be able to prevent certain viruses or bacteria from entering their cells, making them more resistant to disease than cats with lighter-coloured coats. Dark coats also act as a better camouflage for hunting.

Among domestic breeds of cat, the Bengal has an unusual affinity for water. It frequently jumps into its owner's bath, generally uninvited.

Cats have a blind spot, right under their nose. For this reason, they can't find titbits on the floor.

Dogs are not colour-blind; they just don't see the range of colours other species, such as humans, do. A study concluded their world is predominantly made up of yellows and blues. Cats can see limited amounts of colour.

Cats gets stuck up trees because of an evolutionary design fault. Their claws curve under, making them a useful tool for climbing up but less handy when coming down, as they can't grip so effectively. As a result, cats tend to use a far-from-graceful backwards-sliding technique to get out of trees.

• Extracted from Play It Again, Tom by Augustus Brown, published by Bantam Press at £9.99, Augustus Brown. To order a copy (p&p free), call 0845 606 4206.

Thursday, October 18, 2007

Do dogs have a sense of humour? Can they crack jokes? The Daily Telegraph's Washington correspondent, Toby Harnden reckons they can. In fact he thinks his dog Finn is a real practical joker. When Toby tries to put his baby daughter in her car seat, Finn jumps in to block him, flashing a playful smile as he does so. Is he joking? Well, dogs definitely have a sense of humour. They must do, because some things make them laugh. A scientist named Patricia Simonet was the first to notice dogs make “a breathy, pronounced, forced exhalation” that happens exclusively during playtime. She concluded that it’s the canine equivalent of a chuckle. Subsequent tests proved that dogs really like the sound of laughter. One study found that dogs who were played the sound of canine laughter became significantly less stressed and more sociable. The question of what makes a dog laugh though remains unanswered. Darwin’s friend George Romanes reckoned it was a “good joke”. Maybe Finn is proof he was right. Cats, on the other hand, don't laugh. The strange, curling of the top lip they frequently perform may look like an expression of amusement but in fact this is a method of heightening their sense of smell during the mating season. The technique, known as the Flehmen Response, is common in horses, zebras and donkeys too. Cats do signal happiness in different ways, however. They perform a kneading action with their paws. The action is known by various names, from skronking and paddy pawing to making muffins.

Wednesday, October 10, 2007

Dogs can smell electricity, cats can sense epileptic fits. Dogs prefer Bach to Britney Spears, while cats would rather take drugs than eat chocolate. Strange new facts about man's favourite animals - cats and dogs - are being unearthed on a daily basis, it seems. The most curious of these - a dog's bark last on average 0.2 seconds, cats have a secret ultrasonic language - are the subject of my new book, Play It Again, Tom, and an accompanying new blog. If you're not scientifically inclined, don't worry. There are lots of crazy Youtube clips of skateboarding pugs and piano-playing pussycats too!

Monday, March 12, 2007

Scientists have discovered the world’s sharpest and most powerful tongue. And - shock, horror - it doesn’t belong to Simon Cowell. As National Geographic are reporting “the giant palm salamander of Central America (Bolitoglossa dofleini) captures fast-moving bugs with an explosive tongue thrust that releases over 18,000 watts of power per kilogram of muscle”. The scientist behind the discovery, Stephen Deban of the University of South Florida in Tampa, Florida, says the salamander's ballistic tongue-firing mechanism is similar to an arrow being shot from a bow. The "bow" is provided by elastic fibres in the salamander's mouth that stretch to store muscular energy and then release it all at once. The bony tongue is launched with an initial burst of energy and flies forward under its own momentum. The salamander’s extraordinary weapon allow it to fire it’s sticky-padded tip to reach prey in a few thousandths of a second.

Monday, January 22, 2007

Insect Porn Reveals The Shocking Truth: Spiders Squeak During SexThe year is barely a month old, but already I may have stumbled across the most bizarre scientific discovery of 2007. To judge by the truly weird, arachnopornography available at Live Science.Com , female physocylus spiders make a loud squeaking noise during sex. As someone once said, words surpass description.

Monday, January 08, 2007

Thought you might be interested in this piece I wrote for the Family section of last weekend's Guardian. Might explain a little about my strange, possibly unnatural fascination with animals! AB.

I WAS SEVEN when a large sow taught me one of the more valuable, if painful, lessons of my young life: pigs really don't appreciate being ridden, rodeo-style. My moment of enlightenment came one Sunday afternoon, in a muddy pasture on the smallholding where I grew up. Filled with that blend of bravado and brainlessness that only boys of that age possess, I decided to climb on board the fattest of our half dozen or so porkers and "break it in". (I'm fairly certain the idea had been planted by watching a bunch of leathered cowboys taming a steer, earlier that day on Bonanza.)

No sooner had I grasped her leather harness and clambered on board her broad, bristly back, than the sow had shaken off the indolence that had defined her personality since she'd arrived with us and begun performing a passable imitation of a bucking bronco. I held on for all of three seconds before being catapulted, head first, into the mud. The physical bruises faded soon enough; the scars this delivered to my boyhood pride took longer to heal.

Scientists probably don't have catastrophic interactions like this in mind when they talk about the benefits of having animals around. Their arguments tend to focus more on the advantages dogs, cats and hamsters bring in terms of stress-release and proto-parenting, teaching children responsibility and environmental awareness. I have no doubt there is merit in all their assertions. But, it struck me recently, the curious incidents that filled my childhood may offer one or two extra, unheralded arguments in favour of spending our lives close to animals.

When I was 11 or so, for instance, my father and I found a fox cub injured in the woods nearby and brought it home. We nursed it on bottled milk for a few weeks. We converted an old sideboard into his home, even gave him a name, Carlo. No one was more enthusiastic about our new charge than my father, who was fired by memories of his own childhood when he too had reared a stray cub. I remember sensing that our shared responsibility for this poor creature had somehow brought us closer.

One morning I woke up to discover the fox had battered its way through the side of his home and fled. He was gone but he hadn't forgotten. A week later an already more mature-looking Carlo reappeared in a roadside hedge near the entrance to our lane. Rather idiotically, I assumed he'd come back to say thanks. So, unbelievably, did my father. When he kneeled down to stroke the fox, Carlo bit him so hard he almost severed a finger. I'd never seen so much blood. The memory has been locked away ever since, a piece of family lore. Naturally, neither my father nor I has ever trusted a fox since.

In the rural community in which I grew up, animals were part of the daily fabric, especially to my large circle of uncles, many of whom were steeped in the more arcane traditions of country life. One was an accomplished poacher who taught me how to tickle trout. It's a skill I have yet to practice in the Thames tributary that now runs by my home, but you never know when it might come in handy.

Another farming uncle taught me how to spot a sheep that was ready to spontaneously combust. (Hint: if a ewe has been stuck, lying on its side, suffering from "bloat" for several hours and the temperatures are in the 90s, don't light a match anywhere nearby.) Yet another showed me how to read the weather-forecasting skills of cattle and birds. In truth, this was less impressive. It being west Wales, the only weather they tended to predict was rain, which didn't really put them in the Nostradamus class.

The most useless trick a relative passed on to me, undoubtedly, was how to hypnotise a chicken. To my amazement, I saw that by tucking the bird's head under its wings then moving it around slowly in a cyclical fashion, it froze rigid, as if in suspended animation. Unsurprisingly, the beauty of that particular party piece lay in its comedy value. The mere mention of it was enough to reduce the most miserable aunt to laughter. That's another important facet animals bring to family life, of course, as the producers of You've Been Framed have known for decades.

I've spent the bulk of the past 30 years in London, far removed from the rural world in which I was raised. (In reality, it has almost disappeared. Few of the older generation remain and almost all of the old traditions have died away, too.) As a consequence of this, my two young children, Thomas and Gabriella, have missed out on the kind of first-hand animal encounters I took for granted. There have been, of course, memorable moments at zoos and rescue centres, bird parks and nature reserves. Like every other urban family, we've driven round Longleat with baboons attached to the windscreen wipers and wondered at John Aspinall's gorillas at Howlett's in Kent. On holiday in Brazil, we even shared our home with iguanas, macaws and macaque monkeys. The joy these experiences bring the children almost always makes me regret their transience. I feel sad the only foxes they encounter are city scavengers. I often wish they too could do something as daft as learning the art of chicken hypnotism.

This all changed a few months ago, however. It was then that animals - and the simple, sometimes silly pleasures they bestow upon family life - made a small, very small, comeback.

As parents, my wife and I had been resistant to the children's pleas for a cat or dog for a blend of practical and medical reasons. Our home was too confining for a decent-sized dog (and I see no point in having any other). A cat - or any other furry creature - would almost certainly have exacerbated the mild asthma our son, Thomas, occasionally suffered. (Irony of ironies, his first bout was probably triggered by straw mites, encountered during an otherwise brilliant visit to a Devon farm during lambing.) With the latter problem seemingly fading with age, however, our arguments had begun to seem ever more facile.

Then, a year or so ago, I began writing a book on curious animal facts, an assemblage of all the strange things science has taught us about the subjects my country uncles probably knew instinctively. (Cows may not be able to detect rain but, it seems, sharks are capable of detecting bad weather with unerring accuracy.) As talk of how fish communicate by farting (the bright spark that discovered their bubble language named it Fast Repetitive Tick, or FRT) and how mice serenade each other with ultrasonic song flashed across the breakfast table, the children detected the final semblance of their parent's anti-animal resistance melting away. They seized the opportunity with ruthless efficiency. Our home now echoes to the twittering of a four-month-old budgie called Georgie.

Already Georgie is providing the more mundane and obvious benefits those scientists like to talk about. He is a shared responsibility, a warming, unchallenging presence that defuses the stresses of domestic life, a source of entertainment and education. (Did you know budgies are among the most monogamous of all birds? It's partly to do with the fact that females take vicious revenge on a straying male. If he lived in the wild, Georgie would be a hopeless cuckold.)

But he is also beginning to fulfil the role the cows and chickens, foxes and fish played in my country childhood. For a start he generates laughs to rival those produced by talk of hypnotised chickens. You had to be there, of course, but for us the memories of the comic manner in which he fell off his newly installed swing during his first week can produce laughter so violent we fear the children may spontaneously combust.

The little bird's positive influence on the children is already clear. Their Sunday mornings are dedicated to clearing out and cleaning the cage. The budgie's bath times are conducted with diligence and good sense. Pocket money was put aside for a range of Christmas presents for him. He is handled with care and respect. Provided the children keep up their excellent attitude towards the tweating newcomer, other birds - and, who knows, a guinea pig - may follow.

I haven't quite recreated the strange animal-filled landscape of my youth. But I do feel somehow re-connected to the pleasures that a constant, non-human presence can bring. In my more fanciful moments I dream of transforming our home into a place where all manner of animals lie in wait, each of them with a memorable, preferably danger-laced, lesson to deliver Thomas and Gabriella. My wife often accuses me of turning the house into a pigsty. Perhaps we could go the whole hog and stick one or two in the garden.